I miiight need to be corrected here, but if I recall correctly the formula for calculating how many levels worth of summons you can summon is as follows;
[Character Level] * ([Control] / 8) + [Character lv.] so for you it would be:
41 * (2/8) + 41 = 51.25 meaning you can summon 51 levels worth of summons at your current level with your current control.
That would be eg. two Glais (lv. 25 each), or a Crackrock (lv. 40) and a Googoo (lv. 10) etc. (based that off of the encyclopedia, don't really know what can be captured earlier on x_X)
At 8 control you'll be able to summon monsters that total up to twice your character level. (and going past 8 doesn't really do anything anymore?)