[...]

   V --> VgV for all vowels.

 [...]

e.g. in Spanish:

 

   <bueno tiempo> --> <bueguenogo tieguempogo>, I presume.

 

[mariano]

(Writing just as a Spanish native speaker not as phonetist that i'm just amateur) I think that i would transform in that way:

 

    buen tiempo ---> bugueguen tiguiegempogo /buguegen tigiegempogo/

 

The components in diptongs are treated independently each one. 

 

In another example:

 

    rosa y azul --> rogosaga igi agazugul

 

Would happen that althought < y > between vowels has the pronuntiation as a consonant, that is the [j] (with an up-down circunflex instead of the point), it would be understood as a vowel sound. But, in Spanish also, if the following word starts with /i/ then the conjunction < y > use to change to /e/, < e >, as for example in:

 

   bonito e interesante

 

So that allophony for this particular word -the copulative conjunction- is quite extreem and part explicit. The disyunctive conjunction also has explicit allophony, as it is /o/ but becomes /u/ if it's followed by /o/.