Spellbooks and Research in B/X

Ode to Black Dougal has a post about how spellbooks are handled in B/X. In a nutshell, a magic-user or elf may only have a number of spells in their spellbook equal to the number spells they may cast. Thus, a 3rd level magic-user may only have three spells in his spellbook, two 1st level and one 2nd. Further, the only way to add new spells is by researching them yourself and being taught by another caster. No copying from looted spellbooks or copying scrolls.

Being relatively new to the B/X experience, I found this rather jarring. In fact, I mostly glossed over it as a poorly worded passage when I read it. I didn't give it too much thought until I read the blog post. I reread it then and realized that it was worded exactly as intended. In my mind, I immediately houseruled it. I couldn't stop thinking about it, though, and the more I thought about it, the more I liked it. I like what it says about magic-users. I would still houserule two aspects, though.

1. Allow magic-users and elves to modify their spellbook limit by their INT modifier. Allow a total number of additional spells equal to the INT modifier, not to exceed caster level. So, a 1st level caster with an INT of 16 could have one additional 1st level spell. When he reached 2nd level, he could add another 1st level spell, or have two 2nd level spells. These additional spell must still be acquired, they are not freely granted. This does not grant any additional casting ability, either.
2. Looted spellbooks may be used to aid spell research. Per X51, spell research requires 1000 gp and 2 weeks per spell level. It further specifies that this time must be "spent out of campaign". If a looted spellbook is available to reference, this time may be concurrent with adventuring. The other research rules still apply. The spell-caster player must notify the referee when the character is performing his research, such as while other characters are seeking rumors, negotiating with potential hirelings, etc.