From the Class 2 point of view it will depend on what medication you take, how well controlled your diabetes is and whether you have any complications from your diabetes.
http://www.caa.co.uk/docs/49/SRG_MEDNPPLDiabetesV2.pdf
http://www.caa.co.uk/docs/49/SRG_MedDiabeticRx[BothClasses].pdf
http://www.caa.co.uk/docs/49/2008020...nAlgorithm.pdf
These might answer some of your questions.
The NPPL site will be your best source of into about the MTOW etc.
Althought there is some alarm about the fate of the NPPLs when the LAPL comes from EASA.
kui