A Solution to my Conversion Problem?

So my last post, about how the blogosphere seems to be picking back up again, got me thinking about old posts. I've never been the most popular blogger in the OSR. Don't really care to be either. JMal dropped Grognardia because of the flack he took for being the most popular guy around. Well, that and the kickstarter fiasco. Anyway, I'm happy to keep my head down and just plug along. Which is why a post that gets more than 2~3 comments for me is a success.

Anyway, scrolling down my list of posts, I saw this one from a year and a half ago discussing the exact same topic I'm on now -- conversion of the West Marches to Classic D&D.

And it has lots of comments.

Among them, FrDave commented that he lets the players run 5E PCs but he uses Labyrinth Lord for everything on his side of the screen.

I already use a few old school systems in my game. XP for GP. 2d6 Morale checks. 2d6 Reaction Roll checks. I randomly flip between 5E and BECMI treasure tables for loot and magic items.

FrDave mentioned that he gave monsters maximum hit points. Even then, though, 5E monsters have a lot more. A max HP goblin in BECMI has 7 hit points. In 5E, that's the average, the max is 12. A BECMI gnoll has a maximum 16 hit points. In 5E, the average is 22, maximum 40. That's not so different, since I tend to use the averages instead of rolling to save time.

However, when we get to even slightly bigger monsters, it gets stranger. An ogre in BECMI has a max of 33hp, while in 5E its average is 59 and maximum is 91. A gorgon has a max of 64hp in BECMI but an average of 114hp and a max of 164hp.

And of course, it's all about the dragons, really, so let's compare.

A small white dragon (6HD) could have 48hp, but the rules say you can give plus or minus 3, so one with 3HD could only have 24hp and one with 9HD could have 72 hit points. If we use the Masters Set/RC, a huge white dragon (12HD but let's bump it up to 15) could have a max of 120. In 5E, a wyrmling white has average 32hp, maximum 50. The young white has an average of 133, and a maximum of 196. We're at the second age category and already the average hp is higher than the very tip top maximum for a white dragon in BECMI. To make a long story short, the 5E adult white has an average of 200/maximum 288hp, while the ancient white has an average of 333/maximum 504hp.

So at low levels, using 5E PCs with Classic D&D behind the screen might work out alright, it's not suitable to long-term campaigns, unless you like the high level PCs mowing their way easily through flights of dragons and squads of giants the way mid-level PCs go through orcs in older editions.

Still, there's an appeal to doing this. Let the players have their 5E PHBs with their tieflings and eldritch knights and skills and feats and more damage dealing spells than you can shake a stick at. Let me use simple, elegant rules behind the screen.

There's one more hitch, though, which I mentioned to FrDave in that thread and he gave a sort of vague answer. That's saving throws. 5E has you roll d20+ability score to roll over a target number. Old school just has you roll d20 vs a target number that changes as you level up.

So even if I use BECMI or LL behind the screen, players making saving throws are going to want to know the DC to beat. When they cast spells, they expect me to have to roll vs their character's DC. As 5E characters get higher in level, and they boost their stats and proficiency bonus, the DC monsters need to beat goes up. But in BECMI, high HD monsters' saves go down. So if the monster only needs a 5 or better to save by BECMI, but needs a 10 or better to save in 5E, it's not really fair, is it? Lots of spell effects will get saved against.

And the spell effects are different. BECMI sleep spell has no save. 5E lets you roll a save every round. A 5E fireball spell's damage is keyed to the spell slot level used to cast it. A BECMI fireball is keyed to the level/HD of the caster. A 12HD monster can cast fireball for 12d6 damage as a 3rd level spell, while a 5E wizard would need to use a 7th level spell slot to get it to do 12d6 damage (or is it 12d8 in 5E? If so, it's still a 4th level spell slot to get roughly equivalent damage instead of a 3rd).

OK, I started this post out thinking I'd found a workable solution. Now I've convinced myself it's not so workable after all. Or at least at low levels it would be workable enough, but just enough hassle that I might as well stick to the full conversion to my house-ruled Classic D&D system. 100%